1. Field
An embodiment relates to a pixel and an organic light emitting display device using the same, and more particularly, to a pixel that can display an image having desired luminance and an organic light emitting display device using the same.
2. Description of the Related Technology
Recently, a variety of flat panel displays having reduced faults, weight, and volume as compared to cathode ray tubes, have been developed. Flat panel displays include liquid crystal displays, field emission displays, plasma display panels, and organic light emitting display devices, etc.
An organic light emitting display device displays an image, using organic light emitting diodes that emit light generated by recombination of electrodes and holes, has high response speed, and low power consumption.
An organic light emitting display device includes a plurality of pixels that are arranged in a matrix near intersections of a plurality of data lines, scanning lines, and power supply lines. The pixels generally include an organic light emitting diode, a driving transistor for controlling the amount of current that flows in the organic light emitting diode, a storage capacitor for storing a voltage in response to a data signal, and a compensation circuit for compensating for a threshold voltage of the driving transistor.
The pixels store a voltage in response to the data signal and the threshold voltage of the driving transistor in the storage capacitor, and apply current based on the stored voltage to the organic light emitting diode, so that the pixels display an image.
With this configuration, the voltage stored in the storage capacitor should be maintained in order to display an image of the desired brightness. Therefore, at least four transistors are connected in series at a leakage current path thereby preventing the change of the voltage in the storage capacitor.
For example, a first transistor may be formed at a first leakage path that is connected to the storage capacitor, and a second transistor may be formed at a second leakage path. The first transistor and the second transistor are formed by forming at least four transistors in series. However, there is a disadvantage that even though at least four transistors are connected along the leakage path as mentioned above, more than an acceptable level of leakage current is generated, so that the image of the desired luminance may be not displayed. In addition, the storage capacitor is formed to have a large capacitance to compensate for the leakage current in the traditional way, so that there is a disadvantage that aperture ratio of the display is decreased.